Process of concentrating comminuted material.



H. M. SUTTON & W. L. & E. G. STEELE. PROCESS OF COHGENTRATING GOMMINUTED MATERIAL.

APPLICATION FILED. AUG. 29, 1908.

Patnted De0.20,1910.

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1532x061 Saw Affomey H. M. SUTTON @W. L. a; E. G.'STBELE. PROCESS OF OONGENTRATING GOMMINUTBD MATERIAL.

APPLICATION FILED AUG. 29, 190B.

Patented Dec. 20, 1910.

Patented Dec. 20, 1910.

4 SHEETS-SHEET 3- 60 III inin APPLICATION FILED AUG. 29, 1908.

H. M. SUTTON & W. L; & E. a. STEELE: PROGE$S 0P GONGENTRATING GOMMINUTED MATERIAL.

H. M. SUTTON &'W. L. & E. G. STEELE. PROCESS OF OONGENTRATING GOMMINUTED MATERIAL.

APPLICATION FILED AUG- 29, 1908. k Patented Dec. 20, 1910.

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w 0 an A UNITED STATES PA N oEE oE.

HENRY M. SUTTON, WALTER L. STEELE, AND EDWI N- G. STEELE, O-F DALLAS, TEXAS.

PROCESS OF CONCENTRATING COMMINUTED MATERIAL.

Specification of Letters Patent.

Patented Dec'. 20, 1910.

Application filed August 29, 1908. Serial no. 450,918.

To all'whom it may concern:

ing, is a specification, reference being bad therein to the accompanying drawing.

This invention relates to a process of concentrating from a mass of material parts thereof having different.characteristics, and

particularly to a method of dry concentra tion by which the -material is supported upon a cushioning medium, such as, air under pressure, comprising in part a division of application filed Sept. 22, 1906, No.-

saasse,

The process has for an object to supportthe material to be separated upon an air pressure above an inclined pei'vious floor having an unobstructed upper face and subjecting' the material in its passage over said floor to air obstructed areas extending transversely to the path, of travel ofthe relatively lighter components of the material together with a vibration of said floor in the directionof the length ofsaid controlling-areas to'produce a travel of the components ofthe material in diverging paths from whichtliey are separately collected.

A further object .of the invention is to impart to the material a propelling motion in the direction of the length of the controlling areas and other thantlie flow'of the material influenced by gravity so as to utilize the frictional values of the components upon the textile surface of the floor and to propel the material toward the delivery end of the table at a different speed of'moveinentfthan the opposite travel of the table.

Other and further objects and advantages of the invention will be hereinafter fully set forth and the novel features thereof defined by the appended claims. v

In the drawings :Figure 1 isa perspective of one form of concentrating table to carrythis process into effect. Fig. 2 is a vertical cross section of the table reciprocating mechanisnn Fig. 3 is a'similar cross section at right angles to Fig. 2; Fig. 4 is a plan of the table with portions ofitspervious floor broken away; Fig. is a transverse section of the table and of the air chamber beneath the same; Fig. 6 is aneularged cross section of the .floor and air ob structing strips thereunder; Fig. 7 is a plan ofa modified form of table; Fig. 8 is a side elevation of Fig; 7 Fig; 9-is a cross section through the floor of Fig. 7; Fig. 10.,is a plan of a-further modified form of apparatus for carrying the process into effect Fig. 11 is a side elevation thereof; Fig. 12 is a cross-section through the table.

Like numerals refer 'to' like. parts in the several views of the drawings. I

' This process may be carried intoeifect by different forms of apparatus, and in the present case we illustrate several thereof, that shown in Figs.'1 to 6 being similar to the apparatus covered in our application filed September 22, 1906, Serial No. 335,836. In this form, 1 designates a suitable foundation frame for a concentrating table and provided with the cross timbers 2 extended at one side to form a foundation for the-uprights 3 for the support of the hopper 4 and its driving mechanism, Upon the lowerjside of'the table the supports 5 are secured and eachis widened at the top and has a pivotalconnection with the under side of the table to permit reciprocation thereof. At the lower endof the table the supports 5 are provided with semispherical recesses 8 adapted to fit the cooperatingv heads9 of the threaded bolts 10 mounted in the brackets 11 secured to the upper edge and side-of the longitudinal-beam of the mounting of the table adapts the same for a vibrat on or reciprocation longitudinally thereof or in the'gener-aldirection of feedof material from the hopper to the opposite end of. the table. As adesirable means of securing this longitudinal reciprocation a casting 2,7 is mounted upon the foundation 1 provided with bearings 28 adapted to receive 37 is a removable cover adapted to fit the casting 27 and to inclose the bell crank and its operating mechanism. The shorter arm of the bell crank 35 is slotted for the reception of the block 38 and rendered adjustable in the slot by the bolt 39 passing therethrough, the block having trunnions 4:0 for the connection of the yoke 41 which is connected to the table in any desired manner, for instance, the bracket 43 projecting from beneath the table, as shown in Fig. 3. The rod 42 is passed through the bracket and is provided with the washers 44 and lock nuts 45 to adjust the relative inclination of the links to the reciprocating or vibrating means. The lower central portion of the casting 27 comprises an oil chamber and the bearings are grooved to form passages for oil chains 46 over the main channel of the shaft 29 whereby oil is carried thereto for lubricating purposes. Any desired means may be provided for steadying the motion and counterbalancing the weight of the table as it is supported upon the inclined links which incline toward the feed end of the table and for this purpose springs 48 at the lower end of the table are provided. These springs bear at their free end against a portion 50 of the table and are secured at their lower end to the foundation. The extended end 53 of the spring bears against an adjusting bolt 54 mounted in the bracket 55 secured to the foundation which provides means for regulating the tension of the spring 48 against the table.

The bracket 56 is of proper conformation and secured to one of the uprights 3 to form a bearing for the shaft 57 which carries a pulley 58 adapted to be driven from any source of power. This shaft is provided with any well known crank construction 59 connected by rod 60 for reciprocating the feed trough 62- of the hopper 4. This trough is hung by means of rods 64 extending from brackets 65 and secured to the trough at their lower ends. The upper ends of the rods are provided with adjusting nuts 66 for regulating the position of the trough vertically. It will be observed that in the rotation of the shaft 29 in the direction of the arrow in Fig. 3, the longer radius of the eccentric moves directly from over the center of the shaft to the right for a distance of 90 degrees and the first e ,ect is to slide the box 34 toward the pivot of the bell crank thus producing a shorter arm which acts from that point until it reaches a point directly beneath the center of the shaft 29 and thus quickly depresses the longer arm of the bell crank-and through the connecting rods causes a quick return of the table toward the hopper.

The next quarter circle of movement of the long arm of the eccentric first effect a slid mg movement of the box away from the pivot of the bell crank and to act from a point horizontally opposite the center of the shaft 29 to a point vertically over said center, whereby the long arm of said eccentric acts to slowly lift the long arm of the bell crank through the rod connection to slowly reciprocate the table in a direction from the hopper. This produces a slow advance and a quick return of the table, and in view of the inclination of the supports a slow forward and upward movement and a quick backward and return movement caused by the eccentric of the main shaft and the slidable bearings connecting the same with the bell crank. The advantages secured from this peculiar movement will be hereinafter described.

The construction of the table body and top will now be described it being understood that any suitable frame work and air chamber and means for supporting the pervious floor may be employed in lieu of the construction herein disclosed. Referring to Figs. 4, 5 and 6 it will be seen that the cross bars 67 connect the parallel side bars 68 which collectively form the frame work of the table. Upon these side bars, the side pieces 69 are mounted which with the bottom plate 70 constitute the air chamber 71 of the table which communicates with the air inlet connection 71* extending to a blower or other suitable source of pressure. ithin and across the air chamber are arranged several ribs 72 having openings 73 therein to permit access of air under uniform pressure toall parts of the chamber, the purpose of said ribs being to form a support for a series of floor supporting ribs 74 which are suitably connected to thelop frame 75 and bound together by bolts 76, those upon the upper or feed side of the table passing through and securing in posi tion a retaining strip 77. The ribs H extend parallel to each other and longitudinally of the table from the feed toward the delivery portion thereof. as shown in Fig. 4. They may be assembled of separate strips spaced by' blocks 78, as shown at the left of Fig. 5, and held in position by means of the tie bolt extending therethrough. Theright hand portion of Fig. 5 shows the rod 80 passing through the solid wood having the ribs formed thereon and in this con struction proper provision is made for main taining a uniform air pressure against the under surface of the pervious floor 93 of the table. This floor is composed of textile material of desired weave and fineness of mesh which will pass air under pressure upward therethrough so as to act upon the body of material on the floor, while impervious to the passage of such material through the fabric. The table is provided with the delivery shelves 84 and, 85 at the lower side and delivery end respectively, each thereof being provided with the rail 86 supported by spacing tubes 87 through which bolts 88 pass, and by means of nuts 89 passing through the bracket 90 secured in any suitable manner to the sides and ends of the body to support the parts in operative position. The channel bar 76 may be attached to stiffen the table, if desired. The rail 86 is provided for adjusting'the supporting fingers 91 maintained in position by the wedge 92 driven between the'under surface of the rail and the upper edge of the finger whereby the shelfmay be divided into sections constituting chutes or spouts for directing the material in its passage therefrom. 1

For convenience of reference the sides and ends of the table will be designated, althoughthe table may be of any desired shape, and the feed' side of the table at which the hopper is disposed is indicated at F. S., while the opposite delivery side or edge is indicated'by D. S. The end of the floor next the feed hopper is indicated by F. E. and the opposite delivery end by D. E the actual path of the material being clearly indicated in Fig. 1 as proceeding from the hopper divergently toward the delivery end and side, the lighter'particles of the mass thereof traveling transversely over the ribs hereinbefore described and the air retarding or controlling strips 95 carried by these ribs. Referring to Fig. 4, the pervious floor" is shown broken away at the feed and delivery ends of the table and at the feed end the air retarding strips are shown as decreasing in width from the delivery side toward the feed side. upon one of the floor supporting ribs 74, as shown intFig. 6 and extend.longitudinally thereof, each of said strips tapering throughout its length and terminating in a point, and the entire series of separated strips terminating on a diagonal line extending fro-m one corner of the table to the opposite corner thereof as indicated by dotted line in Fig. 4. The air retarding strips are gradually narrower in width from the delivery side to the feed side of the table, and the purpose thereof is to modify .the upward pressure of air through the floor throughout that portion thereof above which the strips are arranged in such a manner that the air increases at increasing distances from the feed side and end of the-table along lines extending longitudinally of the table and decrease upon transverse lines. Fig. 6 illustrates one method of securing the floor and air retarding strips to the supporting ribs 74 although any other suitable means may be used. In this instance, tacks 97 are driven through the floor and retarding strips into the upper edge of the supporting ribs for the purpose of maintaining contact between them and the pervious floor when air pressure is ap- These strips are arranged each plied as otherwise the tendency is to raise the floor from the strips. So far as described the table is freefrom obstructions, such as riffies or any devices performing the function thereof. There is, however, a short bar purpose of preventing the immediate movement of the material toward the delivery end of the tableas it emerges from the chute of the hopper upon the unstripped area at that Joint. These air controlling strips may be 0 such density as to totally obstruct the passage of air through them or to retard or mcdify its action as found desirable, and

may be applied to the under surface of the floor as a strip or as a composition of such character as will not change the textile surface ofthe cloth upon the upper unobstructed surface of the table.

In Figs. 7, 8 and 9 amodified form of table is shown for carrying this process into effect and comprises essentially the bending of the table as shown in Fig. 1 into circular form with a space provided to permit the delivery of the heavier components. Referring to these figures, the numeral 100 designates a base or foundation of any suitable character upon which the table is mounted. This table is formed of any suitable frame work and comprises an air chamber 101 communicating with a source of supply 102 by which air under uniform pressure may be maintained in saidchamber. At the upper portion of the. chamber strips or ribs 103 are suitably supported and extend substantially concentric to the circumference of the table, and each thereof being of greater diameter intermediate of its ends, as shown by dotted lines in Fig. 7. These are applied to the under surface of the pervious top 104 which is unobstructed 'upon its upper face and forms a convex circular floor producing in effect the inclination of the table, as shown in Fig. 1. About the periphery of the table acircular shelf 105 extends and has supported therefrom a bar 106 adapted to support the fingers, as shown in Fig.1, and at the delivery end of the table a similar shelf 107 is formed provided with the bar 108. The material to; be concentrated is fed to the table from the hopper 109 which at.

the top of the inclined portion and supported by a suitable bracket 110 extended upward from the bar. The margin strip 111 70 98 applied adyacent to the hopper for the fected at different speeds as before described for the purpose of propelling the material in the direction of the length of the strips,

and for this purpose a driving shaft 114 is provided with the eccentric 115 of any suitable form which is connected by the rod 116 with the hanger 117 depending from the under surface of the table. Power is applied to the driving shaft from any suitable source through the pulley 118 carried by sa1d shaft. A cleaning up or refining portion of the table is indicated at 119, such portion being devoid of air controlling strips or ribs upon the under surface of the table and corresponds to the similar portion shown in Flg. 1.

In the form shown in Figs. 10, 11 and 12 the table is mounted to permit a gyratory motion thereof, or an oscillation in a gymtory path, and in such form, a frame 120 of any desired character is used from which the table 121 is hung or suspended by the rods 122 pivotally connected to the supporting frame and the table in any desired manner. The table is provided with a flexible air con nection 123 to any suitable source of air pressure, and-the hopper 124 d1sposed to feed upon the table at any preferred point, said hopper being supported by the hanger 125 from the frame. The table itself comprises the air chamber 126, the side walls 127 of which are formed with delivery shelves 128 over which the gangue or lighter material passes. The upper portion of the air chamber is provided with supporting ribs 129 for the air obstructing or controlling strips and above these strips is the PBIVIQHS floor 130 free fromtobstructions upon ts upper surface. The table is provlded at its center with the delivery opening 131 for the heavier components of the material. and, for instance, may be formed. annular, as shown in Figs. 10 and 12. lVithin this opening a sleeve or casing 132 is supported from the table in any desired manner and provided with the cross bar 133 having the hearing 134 for the table driving shaft 135. This shaft is provided at its lower end with the eccentrically disposed weight 136 of any desired character. and the shaft is also formed with the knuckle or universal joints 137 disposed in the desired position to permit the gyratory motion caused by the revolving weight disposed eccentrically to the center of the shaft and the stroke of the table de pending upon the gravity of this weight and its distance from the bearing 136. The upper end of the shaft 135 is mounted in a suitable suspending bearing 138 and provided with the driving pulley 139. The upper surface of the table inclines toward the central opening thereof, as shown in Fig. 12, and the air obstructing strips may be arranged beneath the pervious floor in any desired manner, preferably spiral in shape increasing in width from the center outward forming a tangential line extending from the periphery of the central opening. These strips 140 are of greater width or area at their ends 141 next the periphery of the table than at their inner ends 142 adjacent the periphery of the central opening where they terminate in a point. When this table is given a gyratory motion by the construction just described, the comminuted mass is caused to travel from the upper end moving in advancing circles the diameter of which is equivalent to the extent of the gyratory motion imparted to the table. The air supporting cushion causes the material to stratify, the heaviest being next the surface of the floor with the lightest on top, and the motion of the table causes the material to travel in constantly advancing circles with the heavier material encountering the greater resistance of the textile surface where the same is obstructed by the air controlling strips in contact with the lower surface of the cloth, and have their circular paths checked or modified, their tendency being to follow the direction of the length of these strips which deflects them toward the center. Under the action of the air cushioned textile surface the entire mass is rendered fluid in effect, and the action of the controlling strips causes the particles that are in contact with the surface of the table to form themselves into currents which travel at an angle to those on the surface of the mass and are deflected toward the central discharge. The lighter particles at the top of the stratification are discharged from the outer periphery of the table, as the general direction of their circular paths is from the center toward the outer edge of the table as shown in Fig. 12. The supporting of the material on an air cushioned floor provided with controlling strips causes the deflection of the heavier materials toward the center as these have a tendency to follow the air controlling strips as the fluid movement of the body is restricted at this point. These strips form means to check the velocity of the moving mass and where so checked the heavier material in suspension is deposited on the floor of the table immediately above these strips and continues to accumulate thereon until they are moved to the center of the table and there dischz'lrged. These strips perform the resisting function without the obstructing action of a rittle. This table is designed to treat very finely comminuted material at a capacity far greater than by wet separating methods. Frequently in the separation of crushed ores orl-material some thereof reaches such a fine state of comminution that the gravity of the particles cannot assert itself over its natural adhesion for the surface of the table and cannot take up the forward thrust of the table and be propelled over its surface. These finely comminuted materials can, however, be Stratified on an air cushion and when subjected to the movement of the table the heavier constituents of the mass stratify on the floor thereof where" they may be propelled toward the discharge in the movement of the table.

The discharge of the heavier material through the central opening 131 of the table, as shown in Fig. 12, falls upon a plate 150 which is here shown as annular and disposed beneath the space between the inner wall of the table and the casing 132 which forms The separation ofcertain minerals is 'ma terially facilitated by heating the same prior to their delivery to the table as the surface thereof thus becomes so' altered as to increase or diminish their frictional value and where the separation of two or more components is desired it frequently occurs that the specific gravity aloneis not sufficient to enable such separation which can be. effected if the materials are heatedto a point where the surface of one or more of them is oxidized or changed and then feeding them to the table, thus enabling them to travel over the table at a different rate of speed owing to their greater or lessened frictional value. For instance, in treating ore carrying copper sulfids a heating of the ore to the proper temperature will drive off some of the sulfur from the sulfidsand thus increase the weight of that mineral, as the zinc is not affected at the same temperature. Furthermore the shape of the particles determines the facility with which they are supported on the air cushion. A particle that is spherical is more perfectly supported than a square or sharp cornered one. Freshly crushed ore naturally breaks into different shapes having sharp edges or corners depending upon the crystallization or non crystallization thereof and some of its constituents are more readily fusible than others. Consequently when such a mass is subjected to the proper heat the sharp corners of the more fusible substances become rounded and the facility by which they can be supported on the aircushion is increased. Some of the smooth particles become oxidized or roughened and hence their fric tional value increased so that they are more actively affected by contact with the frictional surface or bed of the table. It is not necessary that the ore be submitted to the table while heated as the heat is used as one means of artificially altering the surface or the specific gravity of the particles in order to-separate it from others upon the textile air cushioned surface of the table. This action may be secured by preliminarily heat-- ing the ore or by subjecting it to a pressure of heated air during the separating action. As one method of thus heating the particles a hopper 146 is shown in Fig. 11 which is provided at its lower portion with an electrical heater 147 connected with circuit wires 148 to any suitable source of energy, and the material therefrom is fed to the table in its heated condition.

It will be understood that the table is inclined transversely to the length of the air controlling strips, and to the travel of the lighter components of the material thereover, and. this inclination may be adjusted as required for different materials to be separated. It is also desirable that these strips be omitted at the delivery from the hopper in order that the material supported upon the air pressure may readily stratify under the cushioning action of the airso that its components will lie in strata relative to their weight, the heaviest being next the textile surface of the floor and the light est at the top. These stratifications assume an angle to the surface of the fioor, and as the particles are cushioned from each other and each stratum likewise cushioned this inclination causes the strata to slide upon each other at the lower corner of the banking strip. At this point they begin to form zones each taking a divergent path diagonally over the table. The formation of the the absence of rifflesor other obstructions upon the upper. surface of vthe floor," while the difference in their frictional value upon the surface of the table, and upon each other, while cushioned under the influence of the air pressure materially assists in the separation as the heavier particles will re place the lighter ones from, the upper portion of the floor where the volume of air is reduced in passing thereover caused by the controlling strips. The difference in frictional value or mobility of the particles is such that the heavier particles travel longitudinally upon the floor or in the path of the controlling strips owing to the reduced air pressure at this pointwhich is insufficient to cushion the heavier particles. The resultis to check their transverse movement, 'and they are therefore-propelled by the longitudinal vibration of the table at different speeds, said propulsion being in a line or. path different from the gravity feed across the table from the feed to the delivery side thereof. The lighter particles the air cushion between the particles is when a small percentage is present. The 1 are sufficiently cushioned by the air so that they meet with comparatively little resistance and travel from the feed to the delivery side' of the table in a path relative to their frictional and gravity resistance. Vhen the table is raised in its forward movement,

more or less compressed which causes the heavier particles to comein contact with the surface of the floor sooner and to remain in contact therewith longer on the return movement of the table than the lighter ones, and this is due to the difl erence in rate of speed at which the particles travel. A fundamental principle .of this process is imparting to the heavier components of the material a travel over the surface or floor of the pervious table in a' direction other than that influenced by gravity by which the particles are caused to travel in diverging paths and may be separately collected. This motion is produced by the vibration of the table in the direction of the length of the-air controlling strips thereon, whether i the same be straight or curved, said motion being changed in character or speed so as to propel the particles in contact with the l table at an angle to the ordinary gravity feed due to the inclination of the table from its feed to the delivery side thereof. This 5 separation is assisted by the difference in frictional value of the different particles of the material relative to the textile surface of the floor, as, for instance, in the separation of zinc ore carrying fluor spar, whichis an ObJGCtlOHEIblQ product in the zmc even specific gravity of fluor spar and zinc blend is substantially the same and the difference is too small to permit successful separation by gravity, but such can be practically effect-ed by the difference of frictional value v of the two minerals as that of zinc blend is 7' much greater than the fluor spar. This frici tional valve may be materially increased or I diminished in different materials by heating the same and feeding them to the floor of the table, thus enabling them to travel thereover at relatively different rates of speed due to the amplified difference in their frictional value.

An important step in this process is the propulsion of the material when supported 1 upon an air cushion across the inclined peri vious floor in a direction at an angle to the length of the air controlling strips there- 5 under or to the ordinary feed by gravity due to the inclination of the floor. If the floor of the table were vibrated in a horizontal plane and without the rising and falling movement it would notcause such a positive propulsion of the heavier components of the material in a direction at an 5 angle to the feed thereof by gravity. The l mass of materials greater frictional value of the particles causes a greater opposition to the feed by gravity and therefore the comminuted material travels in divergent paths across the pervious inclined. floor, those having the greatest specific gravity, or the greatest frictional value traveling more nearly parallel with the air controlling strips, while the lighter components are less affected by such strips and travel more nearly in the path of feed by gravity and transversely to the length of the strips.

It will be obvious that this process may be carried into effect by any desired form of apparatus suitable for the purpose, those herein shown being capable of numerous changes to adapt them to different material to be separated, and are merely shown as instances of means suitable for carrying the process into effect.

\Vhile this invention has been described in connection with the separation of a mixture of gangue and ore, it may be also applied to the separation of different characters of seeds, and cereals, abrasive materials having different characteristics. and granulated or pulverized mixtures of other materials. The air pressure may be regulated. reduced or entirely omitted relative to the specific gravity of the material or-their degree of comminution it being only necessary that they be sufficiently supported to permit their surfaces to contact. with the table so that differential or propelling movement will be transmitted to some of the materials by their frictional contact, while others are fed by gravity in a different path.

Having described our invention and set forth its merits, what we claim and desire to secure by Letters Patent is 1. The process of concentrating from a mass of materials parts thereof having different characteristics consisting in supporting the material upon an unobstructed surface by a gaseous cushioning medium to permit stratification thereof, feeding said material in one path and simultaneously imparting to a portion of said material a positive movement in a direction crossing said path.

2. The process of concentrating from a mass of materials parts thereof having dif ferent characteristlcs consistingin supporting the material upon an unobstructed surface by a gaseous cushioning medium to permit stratification thereof, feeding said material in one )ath and causing portions of said material differing in specific gravity to take directions of travel crossing the direction of movement given vto the material in said path.

3. The process of concentrating from a parts thereof having different characteristics, consisting in feeding the material upon an unobstructed surface, supporting said material by a cushioning air pressure applied in separated parallel areas, and propelling a portion of said material in the direction of such parallelism to separate it from other portions thereof.

4. The process of concentrating from a mass-of materials parts thereof having different characteristics,- consisting in changin the condition of the surface and shape anc consequently the frictional value of some of its particles, supporting the material upon an unobstructed surface by a gaseous cushioning medium to permit Stratification thereof, and feeding said material in one path and simultaneously imparting to a portion of said material a positive movement in a direction across said path.

5. The process of concentrating from a mass of material parts thereof having different characteristics consisting in supporting the material upon an unobstructed surface, feeding it in one path by gravity, supporting said material by a cushioning medium applied in separated parallel areas, and imparting to a portion of said material a propelling movement in the direction of such parallelism and crossing the feed by gravity.

6. The process of concentrating from a mass of materials parts thereof having-dif ferent characteristics, consisting in supporting the material upon an unobstructed surface by a .controlled continuous air pressure applied in separated areas extending transversely to the path of travel of the material by gravity, and imparting to a portion of said material a propelling movement in a direction across the movement of the material by gravity.

7 The process of concentrating from a mass of materials parts thereof having different characteristics, consisting in feeding.

the material upon an unobstructed surface, supporting said material by a continuous controlled air pressure applied in separated areas, and imparting to said material a propelling movement in a circular path. in the direction of the length of said areas.

8; The process of concentrating from a mass of materials parts thereof having different characteristics, consisting in feeding the material by gravity upon an unobstructed surface, supporting said material by a continuous controlled air pressure applied in separated parallel areas, and imparting to a portion of said material a propelling movement in the direction of the length of such tional value of some of its particles, sup

porting said material upon an unobstructed frictional surface by a cushionin applied in separated areas exten ed transversely to the path of travel by gravity of the lighter components of the materials,

medium feeding said material by gravity in a path I transverse tosaid areas and imparting to a portion of said material a propelling movement in a direction across the movement ofthe material by gravity. I

10. The process of concentrating from a mass of materials parts thereof having different characteristics, consisting in supporting said material upon an unobstructed surface by a continuous air pressure applied in parallel and separated areas longitudinal of said surface, and imparting to said materials a propelling movement in the direction of the length of each of said areas.

11. The processof'concentrating from a mass of materials'parts. thereof having different characteristics, consisting in heating the material to increase the frictional value of some of the particles thereof, subjecting the material to a controlled continuous air pressure applied in separated areas beneath an unobstructed frictional surface, and imparting to a portion of said material a propelling movement in the direction of the length of said areas.

12. The process of concentrating from a mass of materials parts thereof having different characteristics, consisting in' heating the material to a degree suflicient to change the frictional surface condition of some of its particles, feedin said material in one path by gravity, and propelling a portion of said materialover an unobstructed frictional surface'in opposition to the feeding thereofby gravity.

In testimony whereof We affix our signatures in presence of two witnesses. I

Witnesses:

E. H. LILLY, 'H. R. PERKINS. 

